(i) Field of the Invention
The invention relates to a packing element for mass transfer or heat transfer columns or towers through which a gas and/or a liquid flows.
(ii) Description of the Prior Art
Such packing elements are known and are used in systematically structured packings in mass transfer and/or heat transfer columns, especially in such columns operated according to the counter-current principle, e.g., distillation, rectification or absorption towers. In such applications, the packing elements consist of lamellae arranged vertically in the direction of flow, the packing element possessing undulations or folds oriented at an angle to the direction of flow. In the packed state, the lamellae of adjacent packing elements intersect and are in contact with each other.
EP 0 158 917 describes a packing element which possesses narrow slits, regularly arranged in each case on the flanks of the undulations or folds, while the edges of the peaks and valleys of the undulations and folds are left unslit. The purpose of this design is to achieve a uniform, and thus optimum, distribution of the counter-current flowing media, and thus to obtain an optimum exchange of media. These known packing elements are effective and create little loss in pressure. However, they possess the disadvantage that this type of packing element, with its regularly arranged slits, is relatively expensive to manufacture.
EP 0 130 745 describes a packing element that can be manufactured from expanded material, which is expanded after the slits have been cut in it. However, such slits then open up disadvantageously in a non-uniform manner. When undulations and folds are subsequently formed in the packing elements, some of the slits are positioned on the peaks or valleys of the undulations or folds, which again results in further irregular opening of the slits. This disadvantageously results in non-uniform distribution of the gas and/or liquid flows. Instead, the flows are arbitrarily distributed and locally different pressure losses occur. In addition, the geometry of the exchange surfaces formed by the surfaces of the packing elements undergoes continual change.